Using water network shapefile and up to date barrier data, river networks can be analysed to show the effects of passable and impassable barriers on fish migration.
For example zooming onto a smaller area in the Combined Essex catchment:
Using geospatial tools, the river network can be split and length of river can be calculated upstream of each barrier.
(Zoom on and hover on the river section to show river length (m)).
Passable barriers: where pass have been installed AND WFD fish priority score <= 2 / Eel regulations priority score <= 2.
Priority scores: 0 - No barrier to fish/eel; 1 - Easy barrier; 2 - Moderate barrier
Waterways open (green) and waterways still remain closed (red).
Habitat Quality Assessment (HQA) is a broad indication of overall habitat diversity provided by natural features in the channel and river corridor.
Habitat Modification Score (HMS) is an indication of artificial modification to river channel morphology.
Metrics on river fish composition, abundance and prevalence.